Vertically translating load/unload ramp mechanism for cold storage data storage device

ABSTRACT

An approach to a reduced-head hard disk drive (HDD) involves a load/unload (LUL) ramp subsystem that includes a ramp assembly that includes a rotatable latch link configured for mechanical interaction with a head-stack assembly (HSA) and a LUL ramp coupled with the latch link, configured such that in response to a force applied to the latch link by the HSA, the latch link rotates which disengages a magnetic latch and drives the LUL ramp to rotate into an operational state disengaged from any recording disk of a multiple-disk stack. The subsystem may further include a motor configured to drive rotation of a lead screw to which the ramp assembly is attached, to drive vertical translation of the ramp assembly, thereby providing for loading the vertically-translatable HSA onto and off of each of the disks of the disk stack.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of and claims the benefit of priorityto U.S. patent application Ser. No. 16/516,195, filed Jul. 18, 2019, nowU.S. Pat. No. 10,706,879, which claims the benefit of priority to U.S.Provisional Patent Application No. 62/700,773, filed Jul. 19, 2018, andto U.S. Provisional Patent Application No. 62/702,556, filed Jul. 24,2018, the entire content of all of which is incorporated by referencefor all purposes as if fully set forth herein.

FIELD OF EMBODIMENTS

Embodiments of the invention may relate generally to a reduced-head harddisk drive having an actuator elevator mechanism and particularly toapproaches to a vertically translating and rotating load/unload rampmechanism.

BACKGROUND

There is an increasing need for archival storage. Tape is a traditionalsolution for data back-up, but is very slow to access data. Currentarchives are increasingly “active” archives, meaning some level ofcontinuing random read data access is required. Traditional hard diskdrives (HDDs) can be used but cost may be considered undesirably high.Other approaches considered may include HDDs with extra large diameterdisks and HDDs having an extra tall form factor, with both requiringlarge capital investment due to unique components and assemblyprocesses, low value proposition in the context of cost savings, andbarriers to adoption in the marketplace due to uniquely large formfactors, for example.

Any approaches described in this section are approaches that could bepursued, but not necessarily approaches that have been previouslyconceived or pursued. Therefore, unless otherwise indicated, it shouldnot be assumed that any of the approaches described in this sectionqualify as prior art merely by virtue of their inclusion in thissection.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments are illustrated by way of example, and not by way oflimitation, in the figures of the accompanying drawings and in whichlike reference numerals refer to similar elements and in which:

FIG. 1 is a plan view illustrating a hard disk drive, according to anembodiment;

FIG. 2A is a perspective view illustrating an actuator subsystem in areduced-head hard disk drive, according to an embodiment;

FIG. 2B is an isolated perspective view illustrating the actuatorsubsystem of FIG. 2A, according to an embodiment;

FIG. 2C is an isolated top view illustrating the actuator subsystem ofFIG. 2A, according to an embodiment;

FIG. 3A is a perspective view illustrating an elevator ramp assembly,according to an embodiment;

FIG. 3B is a perspective view illustrating an elevator ramp assembly,according to an embodiment;

FIG. 4A is a perspective view illustrating a rotatable ramp assembly,according to an embodiment;

FIG. 4B is a top view illustrating the rotatable ramp assembly of FIG.4A in a first operational state within a hard disk drive, according toan embodiment;

FIG. 4C is a top view illustrating the rotatable ramp assembly of FIG.4A in a second operational state within a hard disk drive, according toan embodiment;

FIG. 4D is a perspective view illustrating a vertically translatablerotatable ramp assembly within a hard disk drive, according to anembodiment;

FIG. 5A is a perspective view illustrating a vertically translatablearticulated ramp assembly in a first operational state, according to anembodiment; and

FIG. 5B is a perspective view illustrating articulated ramp assembly ofFIG. 5A in a second operational state, according to an embodiment.

DESCRIPTION

Approaches to a multi-disk hard disk drive having an actuator elevatormechanism and a ramp elevator mechanism are described. In the followingdescription, for the purposes of explanation, numerous specific detailsare set forth in order to provide a thorough understanding of theembodiments of the invention described herein. It will be apparent,however, that the embodiments of the invention described herein may bepracticed without these specific details. In other instances, well-knownstructures and devices are shown in block diagram form in order to avoidunnecessarily obscuring the embodiments of the invention describedherein.

Physical Description of an Illustrative Operating Context

Embodiments may be used in the context of a multi-disk, reducedread-write head, digital data storage device (DSD) such as a hard diskdrive (HDD). Thus, in accordance with an embodiment, a plan viewillustrating a conventional HDD 100 is shown in FIG. 1 to aid indescribing how a conventional HDD typically operates.

FIG. 1 illustrates the functional arrangement of components of the HDD100 including a slider 110 b that includes a magnetic read-write head110 a. Collectively, slider 110 b and head 110 a may be referred to as ahead slider. The HDD 100 includes at least one head gimbal assembly(HGA) 110 including the head slider, a lead suspension 110 c attached tothe head slider typically via a flexure, and a load beam 110 d attachedto the lead suspension 110 c. The HDD 100 also includes at least onerecording medium 120 rotatably mounted on a spindle 124 and a drivemotor (not visible) attached to the spindle 124 for rotating the medium120. The read-write head 110 a, which may also be referred to as atransducer, includes a write element and a read element for respectivelywriting and reading information stored on the medium 120 of the HDD 100.The medium 120 or a plurality of disk media may be affixed to thespindle 124 with a disk clamp 128.

The HDD 100 further includes an arm 132 attached to the HGA 110, acarriage 134, a voice-coil motor (VCM) that includes an armature 136including a voice coil 140 attached to the carriage 134 and a stator 144including a voice-coil magnet (not visible). The armature 136 of the VCMis attached to the carriage 134 and is configured to move the arm 132and the HGA 110 to access portions of the medium 120, all collectivelymounted on a pivot shaft 148 with an interposed pivot bearing assembly152. In the case of an HDD having multiple disks, the carriage 134 maybe referred to as an “E-block,” or comb, because the carriage isarranged to carry a ganged array of arms that gives it the appearance ofa comb.

An assembly comprising a head gimbal assembly (e.g., HGA 110) includinga flexure to which the head slider is coupled, an actuator arm (e.g.,arm 132) and/or load beam to which the flexure is coupled, and anactuator (e.g., the VCM) to which the actuator arm is coupled, may becollectively referred to as a head stack assembly (HSA). An HSA may,however, include more or fewer components than those described. Forexample, an HSA may refer to an assembly that further includeselectrical interconnection components. Generally, an HSA is the assemblyconfigured to move the head slider to access portions of the medium 120for read and write operations.

With further reference to FIG. 1, electrical signals (e.g., current tothe voice coil 140 of the VCM) comprising a write signal to and a readsignal from the head 110 a, are transmitted by a flexible cable assembly(FCA) 156 (or “flex cable”). Interconnection between the flex cable 156and the head 110 a may include an arm-electronics (AE) module 160, whichmay have an on-board pre-amplifier for the read signal, as well as otherread-channel and write-channel electronic components. The AE module 160may be attached to the carriage 134 as shown. The flex cable 156 may becoupled to an electrical-connector block 164, which provides electricalcommunication, in some configurations, through an electricalfeed-through provided by an HDD housing 168. The HDD housing 168 (or“enclosure base” or “baseplate” or simply “base”), in conjunction withan HDD cover, provides a semi-sealed (or hermetically sealed, in someconfigurations) protective enclosure for the information storagecomponents of the HDD 100.

Other electronic components, including a disk controller and servoelectronics including a digital-signal processor (DSP), provideelectrical signals to the drive motor, the voice coil 140 of the VCM andthe head 110 a of the HGA 110. The electrical signal provided to thedrive motor enables the drive motor to spin providing a torque to thespindle 124 which is in turn transmitted to the medium 120 that isaffixed to the spindle 124. As a result, the medium 120 spins in adirection 172. The spinning medium 120 creates a cushion of air thatacts as an air-bearing on which the air-bearing surface (ABS) of theslider 110 b rides so that the slider 110 b flies above the surface ofthe medium 120 without making contact with a thin magnetic-recordinglayer in which information is recorded. Similarly in an HDD in which alighter-than-air gas is utilized, such as helium for a non-limitingexample, the spinning medium 120 creates a cushion of gas that acts as agas or fluid bearing on which the slider 110 b rides.

The electrical signal provided to the voice coil 140 of the VCM enablesthe head 110 a of the HGA 110 to access a track 176 on which informationis recorded. Thus, the armature 136 of the VCM swings through an arc180, which enables the head 110 a of the HGA 110 to access varioustracks on the medium 120. Information is stored on the medium 120 in aplurality of radially nested tracks arranged in sectors on the medium120, such as sector 184. Correspondingly, each track is composed of aplurality of sectored track portions (or “track sector”) such assectored track portion 188. Each sectored track portion 188 may includerecorded information, and a header containing error correction codeinformation and a servo-burst-signal pattern, such as anABCD-servo-burst-signal pattern, which is information that identifiesthe track 176. In accessing the track 176, the read element of the head110 a of the HGA 110 reads the servo-burst-signal pattern, whichprovides a position-error-signal (PES) to the servo electronics, whichcontrols the electrical signal provided to the voice coil 140 of theVCM, thereby enabling the head 110 a to follow the track 176. Uponfinding the track 176 and identifying a particular sectored trackportion 188, the head 110 a either reads information from the track 176or writes information to the track 176 depending on instructionsreceived by the disk controller from an external agent, for example, amicroprocessor of a computer system.

An HDD's electronic architecture comprises numerous electroniccomponents for performing their respective functions for operation of anHDD, such as a hard disk controller (“HDC”), an interface controller, anarm electronics module, a data channel, a motor driver, a servoprocessor, buffer memory, etc. Two or more of such components may becombined on a single integrated circuit board referred to as a “systemon a chip” (“SOC”). Several, if not all, of such electronic componentsare typically arranged on a printed circuit board that is coupled to thebottom side of an HDD, such as to HDD housing 168.

References herein to a hard disk drive, such as HDD 100 illustrated anddescribed in reference to FIG. 1, may encompass an information storagedevice that is at times referred to as a “hybrid drive”. A hybrid driverefers generally to a storage device having functionality of both atraditional HDD (see, e.g., HDD 100) combined with solid-state storagedevice (SSD) using non-volatile memory, such as flash or othersolid-state (e.g., integrated circuits) memory, which is electricallyerasable and programmable. As operation, management and control of thedifferent types of storage media typically differ, the solid-stateportion of a hybrid drive may include its own corresponding controllerfunctionality, which may be integrated into a single controller alongwith the HDD functionality. A hybrid drive may be architected andconfigured to operate and to utilize the solid-state portion in a numberof ways, such as, for non-limiting examples, by using the solid-statememory as cache memory, for storing frequently-accessed data, forstoring I/O intensive data, and the like. Further, a hybrid drive may bearchitected and configured essentially as two storage devices in asingle enclosure, i.e., a traditional HDD and an SSD, with either one ormultiple interfaces for host connection.

Introduction

References herein to “an embodiment”, “one embodiment”, and the like,are intended to mean that the particular feature, structure, orcharacteristic being described is included in at least one embodiment ofthe invention. However, instance of such phrases do not necessarily allrefer to the same embodiment,

The term “substantially” will be understood to describe a feature thatis largely or nearly structured, configured, dimensioned, etc., but withwhich manufacturing tolerances and the like may in practice result in asituation in which the structure, configuration, dimension, etc. is notalways or necessarily precisely as stated. For example, describing astructure as “substantially vertical” would assign that term its plainmeaning, such that the sidewall is vertical for all practical purposesbut may not be precisely at 90 degrees.

While terms such as “optimal”, “optimize”, “minimal”, “minimize”, andthe like may not have certain values associated therewith, if such termsare used herein the intent is that one of ordinary skill in the artwould understand such terms to include affecting a value, parameter,metric, and the like in a beneficial direction consistent with thetotality of this disclosure. For example, describing a value ofsomething as “minimal” does not require that the value actually be equalto some theoretical minimum (e.g., zero), but should be understood in apractical sense in that a corresponding goal would be to move the valuein a beneficial direction toward a theoretical minimum.

Recall that there is an increasing need for cost effective “active”archival storage (also referred to as “cold storage”), preferably havinga conventional form factor and utilizing many standard components. Oneapproach involves a standard HDD form factor (e.g., a 3.5″ form factor)and largely common HDD architecture, with n disks in one rotating diskstack, but containing fewer than 2n read-write heads, according toembodiments. Such a storage device may utilize an articulation mechanismthat can move the heads to mate with the different disk surfaces (for anon-limiting example, only 2 heads but 5+ disks for an air drive or 8+disks for a He drive), where the primary cost savings may come fromeliminating the vast majority of the heads in the drive.

Ramp load/unload (LUL) technology involves a mechanism that moves thehead stack assembly (HSA), including the read-write head sliders, awayfrom and off the disks and safely positions them onto a cam-likestructure. The cam typically includes a shallow ramp on the side closestto the disk. During a power-on sequence, for example, the read-writeheads are loaded by moving the sliders off the ramp and over the disksurfaces when the disks reach the appropriate rotational speed. Thus,the terminology used is that the sliders or HSA are “loaded” to or overthe disk (i.e., off the ramp) into an operational position, and“unloaded” from the disk (i.e., onto the ramp) such as in an idleposition. In the context of a multi-disk HDD having an actuator elevatormechanism, in order to move the heads up and down to different disks theheads need to be backed off the ramp and then re-engaged to the ramp atthe next disk location.

Actuator Subsystem for Reduced-Head Hard Disk Drive

FIG. 2A is a perspective view illustrating an actuator subsystem in areduced-head hard disk drive (HDD), FIG. 2B is an isolated perspectiveview illustrating the actuator subsystem of FIG. 2A, and FIG. 2C is anisolated plan view illustrating the actuator subsystem of FIG. 2A, allaccording to embodiments. FIGS. 2A-2C collectively illustrate anactuator subsystem comprising a low profile ball screw cam assembly 202(or “cam 202”), which transforms rotary motion into linear motion, witha stepper motor 204 (or “stepping motor”) disposed therein to form anactuator elevator subassembly, which is disposed within the actuatorpivot and pivot bearing of the actuator subsystem (e.g., the “pivotcartridge”) and is configured to vertically translate at least oneactuator arm 205 (see, e.g., arm 132 of FIG. 1) along with a respectiveHGA 207 (see, e.g., HGA 110 of FIG. 1). According to an embodiment, theactuator subsystem for a reduced-head HDD consists of two actuator arm205 assemblies each with a corresponding HGA 207 (e.g., a modified HSA,in which the actuator arm assemblies translate vertically, or elevate,while the VCM coil 209 may be fixed in the vertical direction) housing acorresponding read-write head 207 a (see, e.g., read-write head 110 a ofFIG. 1). Generally, the term “reduced-head HDD” is used to refer to anHDD in which the number of read-write heads is less than the number ofmagnetic-recording disk media surfaces.

With respect to electrical signal transmission, FIGS. 2A-2C furtherillustrate a flexible cable assembly 208 (“FCA 208”), which isconfigured to comprise a dynamic vertical “loop” 208 a (“FCA verticalloop 208 a”) for vertical translation of the end(s) that are coupled tothe actuator elevator subassembly and/or another portion of the actuatorsubsystem. This FCA vertical loop 208 a is in addition to a typicaldynamic horizontal loop for horizontal translation purposes for when theactuator to which one end is connected is rotating. The actuatorsubsystem further comprises at least one connector housing 210 forhousing an electrical connector for transferring electrical signals(e.g., motor power, sensor signals, etc.) between the actuator elevatorsubassembly and a ramp elevator assembly (described in more detailelsewhere herein).

With respect to actuator arm locking, FIGS. 2A-2C further illustrate anarm lock subsystem 206, coupled with or constituent to a coil supportassembly 212, configured to mechanically interact with an outer diametercrash stop 211 (“ODCS 211”) to lock and unlock the actuator elevatorsubassembly, as described in more detail elsewhere herein.

Elevator Load/Unload Ramp Assembly for Reduced-Head Hard Disk Drive

One approach to a LUL ramp in the context of a reduced-head HDD may beto employ a traditional static ramp. FIG. 3A is a perspective viewillustrating an elevator ramp assembly, and FIG. 3B is a perspectiveview illustrating a similar elevator ramp assembly (having a slightvariation in the motor carriage configuration), according toembodiments. The elevator ramp assembly or ramp mechanism illustrated ispositioned generally in the area of A-A (FIG. 2A) and comprises amulti-disk ramp 310 and a single ramp adapter 302 coupled to a steppermotor carriage 313 of a stepper motor 312. Thus, the stepper motor 312drives the vertical translation of the ramp adapter 302, so that theramp adapter 302 can be moved, synchronously or asynchronously, inconjunction with an actuator elevator subassembly of an actuatorsubsystem (see, e.g., FIGS. 2A-2C), such that the ramp adapter 302 canmate with a desired “level” of the ramp 310. Each level of the ramp 310corresponds to a respective disk-ramp portion 310 a-310 n of the ramp310 (where n is a number that may vary from implementation toimplementation based on the number of disks in a given HDD), whichcorresponds to the position of a respective disk 120 when installed inan HDD. When the ramp adapter 302 reaches the desired level of the ramp310, then the head-stack assembly (HSA) can be driven by the VCM (see,e.g., the VCM of FIG. 1) to engage with the ramp adapter 302 and thenwith the appropriate level of the ramp 310, such that the HSA canultimately be loaded to an operational position relative to the desireddisk of the multi-disk stack.

The drive mechanism for the ramp adapter 302 comprises the stepper motor312 with carriage 313 (FIG. 3A), 313 a (FIG. 3B), a lead screw 304 withwhich the carriage 313 is translatably coupled, and a support or guiderail 306. As the ramp adapter 302 is fixedly coupled with the steppermotor carriage 313, 313 a, the ramp adapter 302 is driven by therotation of the lead screw 304 under the control of the stepper motor312.

A proximity sensing subassembly, for ramp adapter 302 position sensingand driver feedback purposes, is configured to sense the Z-position(e.g., vertical height) of the carriage 313, 313 a and thus the rampadapter 302. The type/form of sensing mechanism used may vary fromimplementation to implementation. For example, according to anembodiment, sensing is based on the position of the carriage 313, 313 aand the ramp adapter 302 relative to a magnetic encoding strip and,ultimately, relative to the disk stack. The proximity sensingsubassembly comprises a magnetic encoder strip 308 located proximally toat least one corresponding position sensor 314 mounted on the carriage313, 313 a. According to an embodiment, one or more Hall effect sensorsare implemented for the position sensor(s) 314, which function incoordination with the closely-positioned magnetic encoder strip 308mounted on a support structure or stiffener. Generally, a Hall effectsensor (or simply “Hall sensor”) measures the magnitude of a magneticfield, where the output voltage of the sensor is proportional to themagnetic field strength through the sensor. In other embodiments, othermagnetic or non-magnetic based sensing mechanisms may be used forposition detection (see, e.g., the inductive sensing mechanism of FIGS.5A, 5B). A flexible cable assembly (FCA) 316 comprising a vertical“loop” or slack, may be implemented to carry the electrical signals fromthe position sensor(s) 314 to an electrical connector on connecterhousing 210 and onward to some form of controller electronics.

Rotatable Load/Unload Ramp Assembly

A fixed load/unload (LUL) ramp, such as ramp 310 (FIGS. 3A-3B),interfaces with each disk of a multi-disk stack simultaneously, whichwould therefore require more material (e.g., plastic) to form themulti-level ramp. Thus, it is not considered cost-efficient to have sucha multi-level ramp if only one disk needs to be accessed at a time, anda multi-level ramp inhibits the ability to introduce tighter diskspacing within the disk stack.

FIG. 4A is a perspective view illustrating a rotatable ramp assembly,according to an embodiment. Rotatable ramp assembly 400 or rampmechanism comprises a base 402, on which a rotating latch link 404 iscoupled. Rotating latch link 404 is configured for rotation(counter-clockwise) about axis 404 a by physical interaction with a partof the head stack assembly (HSA), such as by interaction with actuatorarm 205 (see, e.g., FIGS. 2A-2C). The latch link 404 is mechanicallycoupled with a rotating ramp holder 406, to which a LUL ramp 410 iscoupled. Note that the ramp holder 406 and ramp 410 may be integratedtogether and formed as a unitary structure, i.e., a single part. As thelatch link 404 is driven to rotate counter-clockwise, ramp holder 406and ramp 410 are driven to overcome magnetic attraction between a magnet407 fixed to the ramp holder 410 and a latch stop 408, and to rotateclockwise up to a point of contact with the latch stop 408, therebymoving the ramp 410 in and out of engagement with a disk of a multi-diskstack.

FIG. 4B is a top view illustrating the rotatable ramp assembly of FIG.4A in a first operational state within a hard disk drive, and FIG. 4C isa top view illustrating the rotatable ramp assembly of FIG. 4A in asecond operational state within a hard disk drive, both according to anembodiment. The operational state depicted in FIG. 4B shows the LUL rampassembly 400, positioned generally in the area of A-A (FIG. 2A), engagedwith a disk (see, e.g., recording medium 120 of FIG. 1) of a multi-diskstack, whereby a distal end of the ramp 410 is positioned so that theouter perimeter of the disk 120 is disposed within a channel at thedistal end of the ramp 410, and with the HSA shown parked on the ramp410. As such, the ramp holder 406 is latched or temporarily fixed by themagnetic attraction between the magnet 407 and the latch stop 408. Thisfirst operational state of the rotatable ramp assembly 400 allows theHSA to be loaded onto a disk for various seek/read/write operations tobe performed by the HSA under the control of the VCM. The operationalstate depicted in FIG. 4C shows the LUL ramp assembly 400 disengagedfrom a disk 120 of a multi-disk stack, whereby the distal end of theramp 410 is positioned so that the outer perimeter of the disk 120 isfree of (i.e., not disposed within) the channel at the distal end of theramp 410, and with the HSA shown removed from the ramp 410, in responseto a sufficient force applied by the actuator arm 205 to the latch link404. As such, the ramp holder 406 is unlatched from the magneticattraction of the latch stop 408 with the magnet 407, and in a rotatedposition with the ramp 410 tip off the disk surface. This secondoperational state of the rotatable ramp assembly 400 allows for diskseek operations (i.e., disk-to-disk translation operations) of the HSAunder the control of the actuator elevator subassembly comprising thecam 202 and in-pivot stepper motor 204 (FIGS. 2A-2C), according to anembodiment. Likewise, the second operational state of the rotatable rampassembly 400 allows for vertical translation of the ramp assembly 400,such as described in more detail in reference to FIG. 4D. In response toremoval of the force applied by the actuator arm 205 to the latch link404, the ramp holder 406 latches again by way of the magnetic attractionbetween the magnet 407 and the latch stop 408, that is, the magneticattraction between the magnet 407 and the latch stop 408 is sufficientlystrong to pull the ramp 410 back into the disk 120 area when theactuator arm 205 recedes from contact with the latch link 404.

FIG. 4D is a perspective view illustrating a vertically translatablerotatable ramp assembly within a hard disk drive, according to anembodiment. The translatable ramp assembly illustrated comprises a rampassembly (similar to rotatable ramp assembly 400, with like-numberedparts configured and operable the same as or similarly to how describedin reference to FIG. 4A) or ramp mechanism, positioned generally in thearea of A-A (FIG. 2A), including a plurality of structural interfaces402 a for coupling with a lead screw 414, configured to be driven by astepper motor 412, and at least one guide rail 416. The stepper motor412 drives the vertical translation of the ramp assembly 400 so that theramp 410 can be moved, when in the second operational state illustratedin FIG. 4C, in conjunction with an actuator elevator subassembly of anactuator subsystem (see, e.g., FIGS. 2A-2C), such that the ramp 410 canmate with a desired disk 120 of a multi-disk stack. When the ramp 410reaches the desired level of the disk stack, then the head-stackassembly (HSA) can be driven by the VCM (see, e.g., the VCM of FIG. 1)to engage with the ramp 410 such that the HSA can ultimately be loadedto an operational position relative to the desired disk of themulti-disk stack, such as with the first operational state illustratedFIG. 4B. According to an embodiment, at least one of the interfaces 402a, such as an interface 402 a associated with the base 402 and/or thelatch link 404, comprises a bushing. According to another embodiment, atleast one of the interfaces 402 a, such as an interface 402 a associatedwith the base 402 and/or the latch link 404, comprises a linear bearing.

A similar proximity sensing subassembly such as illustrated anddescribed in reference to FIGS. 3A-3B (not shown here, for drawingsimplicity and clarity) may be implemented for ramp 410 and/or rampassembly 400 position sensing and driver feedback purposes, andconfigured to sense the Z-position (e.g., vertical height) of the ramp410 relative to a magnetic encoder strip and, ultimately, relative tothe disk stack. That is, according to an embodiment a proximity sensingsubassembly may comprise a magnetic encoder strip (e.g., magneticencoder strip 308 of FIGS. 3A-3B) located proximally to at least onecorresponding position sensor (e.g., position sensor(s) 314 of FIGS.3A-3B) mounted on the ramp assembly 400.

Articulated Load/Unload Ramp Assembly

FIG. 5A is a perspective view illustrating a vertically translatablearticulated ramp assembly in a first operational state, and FIG. 5B is aperspective view illustrating the articulated ramp assembly of FIG. 5Ain a second operational state, both according to an embodiment. Thearticulated ramp assembly 500 or ramp mechanism, positioned generally inthe area of A-A (FIG. 2A), comprises a lever portion 502 or member and aramp portion 510 or member coupled together in a substantially normalrelative positioning (although normal relative positioning is notrequired). The lever portion 502 and the ramp portion 510 are coupledwith a plurality of interconnected structural elevator interfaces 506via a plurality of flexures 504, which act like cantilevered springbeams. At least one of the elevator interfaces 506 is movably coupledwith a lead screw 514, which is configured for driving by a steppermotor 512, while the other elevator interface(s) is movably coupled witha respective guide rail 516. The lever portion 502 is configured fortranslation by physical interaction with a part of the head stackassembly (HSA), such as by interaction with actuator arm 205 (see, e.g.,FIGS. 2A-2C).

FIG. 5A illustrates the articulated ramp assembly 500 in a firstoperational state within a hard disk drive, and FIG. 5B illustrates thearticulated ramp assembly in a second operational state within a harddisk drive. The operational state depicted in FIG. 5A shows thearticulated assembly 500 engaged with a disk (see, e.g., recordingmedium 120 of FIG. 1) of a multi-disk stack, whereby a distal end of theramp portion 510 is positioned so that the outer perimeter of the disk120 is disposed within a channel at the distal end of the ramp portion510, and with the HSA shown parked on the ramp 510. This firstoperational state of the articulated ramp assembly 500 allows the HSA tobe loaded onto a disk for various seek/read/write operations to beperformed by the HSA under the control of the VCM.

The operational state depicted in FIG. 5B shows the articulated rampassembly 500 disengaged from a disk 120 of a multi-disk stack, wherebythe distal end of the ramp 510 is positioned so that the outer perimeterof the disk 120 is free of (i.e., not disposed within) the channel atthe distal end of the ramp 510. As the lever portion 502 is driven totranslate rightward, the flexures 504 are flexed (e.g., in a state ofspring tension) and the interconnected ramp portion 504 is likewisedriven rightward, thereby moving the ramp portion 510 out of engagementwith a disk of a multi-disk stack. As such, the ramp portion 510 is in atranslated position with the ramp tip off the disk surface. This secondoperational state of the articulated ramp assembly 500 allows for diskseek operations (i.e., disk-to-disk translation operations) of the HSAunder the control of the actuator elevator subassembly comprising thecam 202 and in-pivot stepper motor 204 (FIGS. 2A-2C), according to anembodiment. Likewise, the second operational state of the articulatedramp assembly 500 allows for vertical translation of the ramp assembly500, such as described in more detail elsewhere herein.

Note that the illustrations of FIGS. 5A-5B depict the flexures 504 in arelaxed or neutral position when the ramp portion 510 is engaged withthe disk 120, and in a flexed position (e.g., in a state of springtension) when the ramp portion 510 is disengaged from the disk 120.However, this arrangement may vary from implementation toimplementation, as the articulated ramp assembly 500 may be configuredso that the flexures 504 are in a relaxed or neutral position when theramp portion 510 is disengaged from the disk 120 and in a flexedposition when the ramp portion 510 is engaged with the disk 120.

Similarly to the rotatable ramp assembly 400 (see, e.g., FIG. 4A), thearticulated ramp assembly 500 is considered a vertically translatablearticulated ramp assembly within a hard disk drive, according to anembodiment, in view of the plurality of structural elevator interfaces506 configured for coupling with a lead screw 514, configured to bedriven by a stepper motor 512, and at least one guide rail 516. Thestepper motor 512 drives the vertical translation of the ramp assembly500 so that the ramp portion 510 can be moved, when in the secondoperational state illustrated in FIG. 5B, in conjunction with anactuator elevator subassembly of an actuator subsystem (see, e.g., FIGS.2A-2C), such that the ramp portion 510 can mate with a desired disk 120of a multi-disk stack. When the ramp portion 510 reaches the desiredlevel of the disk stack, then the head-stack assembly (HSA) can bedriven by the VCM (see, e.g., the VCM of FIG. 1) to engage with the rampportion 510 such that the HSA can ultimately be loaded to an operationalposition relative to the desired disk of the multi-disk stack, such aswith the first operational state illustrated FIG. 5A. As with therotatable ramp assembly 400, at least one of the elevator interfaces 506may comprise a bushing and/or at least one of the elevator interfaces506 may comprise a linear bearing.

While a similar proximity sensing subassembly such as illustrated anddescribed in reference to FIGS. 3A-3B may be implemented for rampassembly 500 position sensing and driver feedback purposes, andconfigured to sense the Z-position (e.g., vertical height) of the rampportion 510 relative to a magnetic encoder strip, according to anembodiment a sensor 508 is coupled with a portion of the ramp assembly500 and positioned as illustrated in FIGS. 5A-5B in order to directlysense the location of the disk edge, rather than sensing the positionbased on an object remote from the disk stack (e.g., a magnetic encoderstrip). According to an embodiment, a non-contact inductive proximitysensor, and associated electronic circuitry 508 a, is utilized forsensor 508 and is positioned as close to the disk stack as practicallyfeasible. As such, inductive sensor 508 relies on the principle ofelectromagnetic induction and is implemented in the form of one or morecoils embedded in a flexible printed circuit (FPC) and/or flexible cableassembly such as a portion of or an electrical extension of FCA 513,which may ultimately tie in with FCA 208 (FIGS. 2A-2C). In one form ofinductive sensor 508, a coil (e.g., an inductor, such as in an LCRcircuit comprising an inductor, capacitor, and resistor) may be used togenerate a varying magnetic field and another coil may be used to detectchanges in the magnetic field introduced by a metallic object, such asthe nickel-plating covering the edge of disk 120. In another form ofinductive sensor 508, a metallic object (such as the nickel-platingcovering the edge of disk 120) moving past the coil(s) will alter theinductance in the coil and hence the resonant frequency of the LCRcircuit electrically coupled to the electronic circuitry 508 a, wherebythe change in resonant frequency is detected. The electronic circuitry508 a then converts this change in resonant frequency to a standard DAC(digital-to-analog converter) output, which can be used for servocontrol of the stepper motor 512. Hence, the change in resonantfrequency of the inductive sensor 508, when moving from media to air gapto media, can be detected and, therefore, the positioning of the rampassembly 500 relative to the disk stack can likewise be determined.However, the type/form of sensing mechanism used may vary fromimplementation to implementation.

EXTENSIONS AND ALTERNATIVES

In the foregoing description, embodiments of the invention have beendescribed with reference to numerous specific details that may vary fromimplementation to implementation. Therefore, various modifications andchanges may be made thereto without departing from the broader spiritand scope of the embodiments. Thus, the sole and exclusive indicator ofwhat is the invention, and is intended by the applicants to be theinvention, is the set of claims that issue from this application, in thespecific form in which such claims issue, including any subsequentcorrection. Any definitions expressly set forth herein for termscontained in such claims shall govern the meaning of such terms as usedin the claims. Hence, no limitation, element, property, feature,advantage or attribute that is not expressly recited in a claim shouldlimit the scope of such claim in any way. The specification and drawingsare, accordingly, to be regarded in an illustrative rather than arestrictive sense.

In addition, in this description certain process steps may be set forthin a particular order, and alphabetic and alphanumeric labels may beused to identify certain steps. Unless specifically stated in thedescription, embodiments are not necessarily limited to any particularorder of carrying out such steps. In particular, the labels are usedmerely for convenient identification of steps, and are not intended tospecify or require a particular order of carrying out such steps.

What is claimed is:
 1. A method for vertically translating a load/unload (LUL) ramp mechanism in a hard disk drive (HDD) to provide access to each of a plurality of recording disks, the method comprising: driving a stepper motor to rotate a lead screw coupled to the stepper motor; and allowing a LUL ramp mechanism that is coupled with the lead screw to translate vertically in response to rotating the lead screw, wherein allowing the LUL ramp mechanism to translate comprises: providing one or more guide rails configured to interface with a respective corresponding interface of the LUL ramp mechanism; providing a first interface constituent to a latch link component of the LUL ramp mechanism, wherein the first interface is positioned around a first guide rail of the one or more guide rails.
 2. The method of claim 1, wherein allowing the LUL ramp mechanism to translate further comprises: providing a second interface constituent to a base component of the LUL ramp mechanism, wherein the second interface is positioned around a second guide rail of the one or more guide rails.
 3. The method of claim 2, wherein allowing the LUL ramp mechanism to translate further comprises: providing a third internally threaded interface constituent to the base component and positioned around the lead screw.
 4. The method of claim 2, wherein allowing the LUL ramp mechanism to translate further comprises: providing a bushing for at least one of the first interface and the second interface.
 5. The method of claim 2, wherein allowing the LUL ramp mechanism to translate further comprises: providing a linear bearing for at least one of the first interface and the second interface.
 6. The method of claim 1, further comprising: while the LUL ramp mechanism is translating, determining the vertical position of the LUL ramp mechanism. 